Pycnogenol inhibits the release of histamine from mast cells.

Oxygen derived free radicals are now increasingly regarded as a primary force of tissue destruction and also have the ability to release histamine from mast cells. Pycnogenol is an extract of the bark of French maritime pine (Pinus pinaster) containing bioflavonoids with a potent ability to scavenge free radicals. Therefore Pycnogenol was investigated for inhibition of histamine release from rat peritoneal mast cells. In addition, its effects were compared with sodium cromoglycate, a known inhibitor of histamine release from the mast cell. Rat peritoneal mast cells were isolated and purified by differential centrifugation and cells pooled from 3-4 animals were suspended at approximately 10(6) cells/mL buffered salt solution. Histamine release was induced by compound 48/80 or the calcium ionophore A-23187 and estimated from supernatant following extraction and by fluorimetric methods. Pycnogenol produced a concentration dependent inhibition of histamine release induced by the two secretagogues. Its inhibitory effect on mast cell histamine release was favourably comparable to sodium cromoglycate.